Airbags today are made from woven material which is usually nylon or, more recently, polyester. This material is frequently coated with either neoprene or silicon rubber which results in a material having substantial mass and which can cause an occupant to be injured when struck by an inflating airbag. According to one estimate, as many as one third of all of the occupants that are involved in car crashes where the airbag deploys are injured by the airbag. Those that are unfortunate enough to be resting against the airbag when it deploys can be seriously injured or even killed by the airbag cover or deployment door as the airbag initially emerges from its housing. However, the vast majority of the cases involve impact injuries between the airbag fabric and the occupant's face or arms. Experimental results published in a recent Society of Automotive Engineers paper show that the cause of the injury is from the momentum of the bag material as it strikes the occupant and not from abrasion of the airbag rubbing on the occupant.
Airbag systems today are designed so that ideally the airbag is fully inflated before the occupant moves into the space which will be occupied by the airbag. However, most occupants are not positioned at the ideal location assumed by the airbag system designer. Many occupants sit very close to the airbags and thus are injured by the airbag deployment and others sit far from the airbag and therefore must travel some distance before receiving the benefit of the airbag.
Severe out of position occupant situations, where the occupant is resting against the airbag when deployment begins, can only be handled using an occupant position sensor, such as disclosed in copending patent application Ser. No. 08/040,978 which prevents an airbag from deploying if an occupant is more likely to be seriously injured by the airbag deployment than from the accident itself. In many less severe accidents, the occupant will still interact with the deploying airbag and sustain injuries ranging from the mild to the severe. In addition, some occupants sit very far from the steering wheel or instrument panel and, with conventional airbags, a significant distance remains even after the airbag is fully inflated. For these reasons it would be desirable to have an airbag system that adjusts to the location of the occupant and where the impact of the airbag causes little or no injury.
Airbags made from plastic film have heretofore not been used. One reason is that if a film bag is as large as a conventional airbag it must also be quite strong and therefore nearly as heavy as a woven airbag. This results from the fact that if a film airbag is punctured it can fail catastrophically like a bursting balloon.
There is a great deal of concern today for the safety of a child in a rear facing child seat when it is used in the front seat of an airbag equipped vehicle. The passenger side airbag has sufficient force to cause significant injury to a child sitting in such a seat and parents are warned not to use child seats in the front seat of a vehicle having a passenger side airbag. Several automobile companies are now experimenting with rear seat airbags where the child seat problem would be compounded. Also, especially on long trips, children frequently lie down in the front or rear seats of the vehicle to sleep. Present airbag systems are incapable of protecting such occupants who will slide underneath the airbag.
Airbags are designed to interact with an occupant in a symmetrical fashion. Many accidents have substantial angularity resulting in an occupant impacting with one edge of the airbag and thereafter sliding off of the airbag without receiving it's full protection capability.
These and many other problems associated with current airbags are solved by the airbag designs disclosed in the paragraphs below.